INDIANAPOLIS — The NFL scouting combine doesn't end until Tuesday, but media availability wrapped Sunday afternoon. Here are four takeaways:

Cautious quarterbacks

Top quarterbacks Johnny Manziel of Texas A&M and Teddy Bridgewater of Louisville passed on throwing here, opting to wait for on-campus events next month instead. Fresno State QB Derek Carr sat out, too. Every coach and general manager likes to see players compete, and Cam Newton is proof a lousy combine showing doesn't necessarily harpoon chances of becoming the No. 1 pick. But it's hard to fault a player with so much on the line for wanting to throw in a controlled environment, to familiar receivers, on a script designed to showcase his strengths. Credit Central Florida QB Blake Bortles — who measured in at 6-foot-5 and 232 pounds, towering over Manziel (5-11¾, 207) and Bridgewater (6-2, 214) — for taking a (small) chance and showing off his arm.

Speed matters

Manziel, whose hands measured at a gigantic 9 7/8 inches, did run the 40-yard dash and posted an official time of 4.68 seconds — good for fourth-best among quarterbacks. Sunday's burner was Kent State running back Dri Archer, who ran the 40 in 4.26, just two-hundredths of a second off Chris Johnson's combine record. None of the drills here are the end-all, be-all of evaluations for teams. But for lower-profile players such as Archer, who entered the week as a projected late-round pick or free agent, displaying a dominant trait can be enough to make scouts take a second look at the tape before the draft begins May 8. Clemson's Sammy Watkins, widely regarded as the draft's top receiver, said he was taking aim at Johnson, too. Watkins was timed at 4.43.

Defensive linemen and linebackers work out today, giving teams an up-close look at two players in focus for different reasons: South Carolina DE Jadeveon Clowney and Missouri DE Michael Sam. Clowney is as physically gifted as any player in the draft and figures to be under consideration for one of the draft's top two picks, depending on whether the Houston Texans and St. Louis Rams stay put. But rumblings about his work ethic and passion persist. There are no such concerns about Sam, who hopes to become the NFL's first openly gay player. But he knows he must answer questions about how a pass rusher with his size (6-2, 261) and athletic limitations fits into an NFL scheme or he'll slip into the late rounds. Workouts wrap with defensive backs Tuesday.

NFL rules bar teams from negotiating with other teams' free agents until March 8, just before the market opens. All over the city, team executives could be seen meeting with agents — not that many numbers were exchanged. No agent will just sit on an offer for two weeks, so teams are careful about showing their cards. The post-combine lull can have a chilling effect on spending as teams get a better handle on how to fill their holes through the draft. That's a big reason a small group of agents meeting with union officials Thursday discussed the possibility of moving up the start of free agency immediately after the combine in future years, which would have to be collectively bargained with the league.

Some explaining to do

There is damage control to be done in San Francisco after multiple reports during the combine — confirmed to USA TODAY Sports by Browns owner Jimmy Haslam — the 49ers discussed a trade that would have sent coach Jim Harbaugh to Cleveland. A team that has reached three consecutive NFC title games under Harbaugh now faces an offseason's worth of questions about his future and the dynamic of the football operation. One way to answer them would be to extend Harbaugh's contract, which has two years remaining. But that may not be easy, especially if Harbaugh is angling for more power on top of a bar-setting contract before he has won a Super Bowl.

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